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A quick and selective analytical method was developed employing LC-MS/MS for the quantitation of matrine. This is known to be a natural ingredient of Sophora ssp. and is suggested to be a potential contaminant, e.g. in herbal raw materials from liquorice or confectionery products based on liquorice. To prove that the finding of matrine in liquorice roots does not originate from an active use of pesticides, wild collection areas, as well as geographical, legal and economic aspects have been studied with the help of experienced traders and suppliers in cooperation with local liquorice producers. An LC-MS/MS method was successfully developed and applied for monitoring of raw material and semi-finished products (N = 104) and afterwards a model test was performed to show that findings of matrine in liquorice products originates from a co-harvesting of nearby growing Sophora roots during the manual collection of liquorice roots.

This study evaluates the content and formation of free and bound monochloropropanediol (MCPD) and bound glycidol (GE) in fine bakery wares from the German market. The analytical screening revealed, that free 3-MCPD can be quantified in products with low water and fat content, which are produced using high baking temperatures. Concentrations resulted to be 10.0 µg/kg (wafers), 14.1 µg/kg (crispbread) and 22.8 µg/kg (rusk) and are thus judged to be of minor significance when it comes to a potential introduction of a combined maximum level for free and bound species. As exception, considerable amounts of free 3-MCPD (maximum level of 265.4 µg/kg) were only quantified in cinnamon stars containing glycerine as additive. As expected, MCPDE were only quantified in products produced with refined vegetable oil (short bread, puff pastry, caramel biscuits, speculoos, cake, wafers, wholemeal biscuits and rusk). GE levels have already been significantly reduced compared to former studies, one cake showed a maximum content of 127.8 µg/kg. A model baking trial using 13C-3-MCPDE spiked butter as fat component in shortbread confirmed that free 3-MCPD and 2-MCPD, 3-MCPDE, 2-MCPDE or GE are not endogenously formed in marketable browned biscuits. A thermal or lipase-catalysed release of free 3-MCPD from its fatty acid esters can be excluded.

In recent years, operating rooms (ORs) have transformed into integrated operating rooms, where devices are able to communicate, exchange data, or even steer and control each other. However, image data processing is commonly done by dedicated workstations for specific clinical use-cases. In this paper, we propose a concept for a dynamic service component for image data processing on the example of automatic image quality assessment (AQUA) of intraoperative cone beam computed tomography (CBCT) images. The service is build using the Open Surgical Communication Protocol (OSCP) and the standard for Digital Imaging and Communications in Medicine (DICOM). We have validated the proposed concept in an integrated demonstrator OR.

We present an interactive segmentation method for 3D medical images that reconstructs the surface of an object using energy-minimizing, smooth, implicit functions. This reconstruction problem is called variational interpolation. For an intuitive segmentation of medical images, variational interpolation can be based on a set of user-drawn, planar contours that can be arbitrarily oriented in 3D space. This also allows an easy integration of the algorithm into the common manual segmentation workflow, where objects are segmented by drawing contours around them on each slice of a 3D image. Because variational interpolation is computationally expensive, we show how to speed up the algorithm to achieve almost real-time calculation times while preserving the overall segmentation quality. Moreover, we show how to improve the robustness of the algorithm by transforming it from an interpolation to an approximation problem and we discuss a local interpolation scheme. A first evaluation of our algorithm by two experienced radiology technicians on 15 liver metastases and 1 liver has shown that the segmentation times can be reduced by a factor of about 2 compared to a slice-wise manual segmentation and only about one fourth of the contours are necessary compared to the number of contours necessary for a manual segmentation.

Bacillus megaterium was used in biotransformation studies to test the influence of several barbiturates towards the recently observed N-dealkylation and arylic hydroxylation of N,N-diethylaniline. Certain barbiturates (phenobarbital and amobarbital) induced increased enzyme activity in whole-cell incubations with B. megaterium resulting in an increasing amount of N-deethylated and hydroxylated arylic (ortho- and para-hydroxylation) products, whereas ortho-hydroxylation was slightly favored. Phenobarbital did not show any effects towards hydroxylation activity, but N-dealkylation activity was highly induced. Finally, metyrapone highly reduced hydroxylation and N-dealkylation activity.

Female choice is thought to increase the fitness returns of females. The complementary choice model states that the best mate depends on the particular genotype of a female. Aculeate Hymenoptera represent a special case of complementary female choice because males should be chosen on the basis of their allele at the sex determination locus. The prevalent sex determination mechanism in bees and wasps (single-locus complementary sex determination) requires that, to produce a daughter, diploid offspring are heterozygous at the sex determination locus. Otherwise, infertile diploid males result. Inevitably, the proportion of diploid males increases with the rate of inbreeding. In the European Beewolf, males scent mark territories to attract mates and the composition of the pheromone might provide a basis for female choice. One crucial prerequisite for females to be able to discriminate against brothers and avoid inbreeding is that the male sex pheromone varies with familial affiliation. This hypothesis was tested by analysing the pheromone of male progeny of eight mothers using gas chromatography and mass spectrometry. A significantly higher similarity was found among brothers than among unrelated individuals. Such a genetic component of a male sex pheromone has not yet been described from aculeate Hymenoptera. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 89, 433–442.

The δ13CVPDB and δ18OVSMOW values of caffeine isolated from commercial caffeine-containing foods were determined by isotope ratio mass spectrometry (IRMS) using elemental analysis (EA) in the 'combustion' (C) and 'pyrolysis' (P) modes (EA-C/P-IRMS), respectively. In total, 69 samples (32 guarana products, 20 teas, 12 coffee products, and 5 mate teas) were analyzed together with three references of synthetic caffeine. Validation was done by excluding isotope discrimination in the course of sample preparation and determining linear dynamic ranges for EA-P-IRMS measurements. In total, five samples (one caffeine-containing soft drink and four guarana products) under study contained synthetic caffeine.

In this account, we summarize the highlights of our cooperative research work on the biocatalytic preparation of enantiomerically enriched, oxyfunctionalized substances in the ‘Sonderforschungsbereich (SFB 347): Selektive Reaktionen Metall-aktivierter Molekule’. The biocatalytic kinetic resolution of secondary hydroperoxides with the metalloenzymes horseradish (HRP) and Coprinus (CiP) peroxidase affords the hydroperoxides and their alcohols in excellent enantiomeric excess. Also the semisynthetic enzyme selenosubtilisin catalyzes effectively the enantioselective reduction of racemic hydroperoxides to produce optically active hydroperoxides and alcohols in high ee values. The asymmetric CH oxidation of long- and medium-chain carboxylic acids by molecular oxygen, catalyzed with the α-oxidase from pea leaves or germinating peas yields enantiomerically pure 2-hydroxy acids. The enzymatic kinetic resolution of racemic 2-hydroxy acids through the enantioselective oxidation by glycolate oxidase (GOX) or the esterification by lipase provides an attractive route to such optically active building blocks. The bacteria Bacillus subtilis and Bacillus megaterium , isolated from topsoil by selective screening with hydrogen peroxide or allylbenzene, are efficient biocatalysts for the enantioselective reduction of racemic hydroperoxides and the asymmetric CH oxidation of alkanes. The latter enzymatic process is to date still difficult to emulate by chemical catalysis.

Efficient segmentation editing tools are important components in the segmentation process, as no automatic methods exist that always generate sufficient results. Evaluating segmentation editing algorithms is challenging, because their quality depends on the user’s subjective impression. So far, no established methods for an objective, comprehensive evaluation of such tools exist and, particularly, intermediate segmentation results are not taken into account. We discuss the evaluation of editing algorithms in the context of tumor segmentation in computed tomography. We propose a rating scheme to qualitatively measure the accuracy and efficiency of editing tools in user studies. In order to objectively summarize the overall quality, we propose two scores based on the subjective rating and the quantified segmentation quality over time. Finally, a simulation-based evaluation approach is discussed, which allows a more reproducible evaluation without the need for human input. This automated evaluation complements user studies, allowing a more convincing evaluation, particularly during development, where frequent user studies are not possible. The proposed methods have been used to evaluate two dedicated editing algorithms on 131 representative tumor segmentations. We show how the comparison of editing algorithms benefits from the proposed methods. Our results also show the correlation of the suggested quality score with the qualitative ratings.

In oncological chemotherapy monitoring, the change of a tumor's size is an important criterion for assessing cancer therapeutics. Measuring the volume of a tumor requires its delineation in 3-D. This is called segmentation, which is an intensively studied problem in medical image processing. However, simply counting the voxels within a binary segmentation result can lead to significant differences in the volume, if the lesion has been segmented slightly differently by various segmentation procedures or in different scans, for example due to the limited spatial resolution of computed tomography (CT) or partial volume effects. This variability limits the sensitivity of size measurements and thus of therapy response assessments and it can even lead to misclassifications. We present a fast, generic algorithm for measuring the volume of solid, compact tumors in CT that considers partial volume effects at the border of a given segmentation result. The algorithm is an extension of the segmentation-based partial volume analysis proposed by Kuhnigk for the volumetry of solid lung lesions , such that it can be applied to inhomogeneous lesions and lesions with inhomogeneous surroundings. Our generalized segmentation-based partial volume correction is based on a spatial subdivision of the segmentation result, from which the fraction of tumor for each voxel is computed. It has been evaluated on phantom data, 1516 lesion segmentation pairs (lung nodules, liver metastases and lymph nodes) as well as 1851 lung nodules from the LIDC-IDRI database. The evaluations of our algorithm show a more accurate estimation of the real volume and its ability to reduce inter- and intra-observer variability significantly for each entity. Overall, the variability (interquartile range) for phantom data is reduced by 49% ( p ≪ 0.001) and the variability between different readers is reduced by 28% ( p ≪ 0.001). The average computation time is 0.2 s.

Segmentation is one of the main tasks in medical image analysis. Measuring the quality of 3D segmentation algorithms is an essential requirement during development and for evaluation. Various methods exist to measure the quality of a segmentation with respect to a reference segmentation. Validating interactive 3D segmentation approaches or methods for 3D segmentation editing is more complex, however. Using interactive tools, the user plays a central role during the segmentation process as he or she needs to react on intermediate results, making established static validation approaches insufficient. In this paper we present a method to automatically generate plausible user inputs for 3D sketch-based segmentation editing algorithms, to allow an objective and reproducible validation and comparison of such tools. The user inputs are generated iteratively based on the intermediate and the reference segmentation, while static quality measurements are tracked over time. We present first results where we have compared two segmentation editing algorithms using our framework.

Soil samples were screened to select microorganisms with the capability to oxidize organic sulfides into the corresponding sulfoxides with differential enantioselectivities. Several bacterial strains that preferentially produced the S- configured sulfoxide enantiomer were isolated. Surprisingly, one bacterial strain, genotypically and phenotypically characterized as Pseudomonas frederiksbergensis , selectively gave the R enantiomer. The finding that two apparently identical organisms displayed opposite enantioselectivities is novel for non-genetically modified organisms.